We propose to study cell-substratum adhesion. Our long-term goal is to determine the cell surrface and cytoplasmic components involved in adhesion and how these differ - if at all - between normal and malignant cells. To this end we plan to carry out biochemical and ultrastructural analyses of cells during adhesion and spreading under a variety of conditions. Current investigations are directed at further elucidation of the action of cell adhesion and spreading factor (ASF). This mixture of several active serum glycoproteins is required to be adsorbed onto the substratum surface in order for physiological adhesion of cells to occur to the substratum. We plan to study the binding of ASF to the cell surface and its topographical organization during cell adhesion and spreading. Chemical modification of ASF may provide important insights into the functional groups of the glycoprotein. Direct isolation of surface receptors for ASF is planned. In addition to these studies, experiments are planned on perturbation of cell adhesion and spreading by various cell surface ligands and on changes in the distribution of anionic sites during cell adhesion and spreading. BIBLIOGRAPHIC REFERENCES: Grinnel, F. (1976) The serum dependence of baby hamster kidney cell attachment to a substratum. Exp. Cell Res. 97:265-274. Grinnel, F. (1977) Induction of cell adhesion and cell spreading by various cell surface ligands. Presented at 1977 ICN-UCLA Symposium on Cell Surface Carbohydrates and Biological Recognition.